Epidemiology of native kidney disease in Flanders: results from the FCGG kidney biopsy registry
Wim Laurens, Dries Deleersnijder, Amélie Dendooven, Evelyne Lerut, An S. De Vriese, Tom Dejagere, Mark Helbert, Rachel Hellemans, Priyanka Koshy, Bart Maes, Lissa Pipeleers, Amaryllis H. Van Craenenbroeck, Steven Van Laecke, Johan Vande Walle, Marie M Coutteneye, Johan De Meester, Ben Sprangers, The FCGG collaborative group, An S. De Vriese, Anja De Rycke, Anne-Marie Bogaert, Annemie Woestenburg, Bart Denys, Bart Maes, Domien Peeters, Hilde Vanbelleghem, Jan Donck, Johan Scharpé, Nele De Clippeleir, Joris Vanparys, Karen Meyvis, Kurt Vandepitte, Liza-Maria Reyns, L. Verresen, Marc Decupere, Mark Helbert, Miranda Zeegers, Nathalie Neirynck, Pascale Bernaert, Tom Dejagere, Wim Lemahieu, Ben Sprangers, Lissa Pipeleers, Rachel Hellemans, Steven Van Laecke, Elena Levtchenko, Sevasti Karamaria, Koen Van Hoeck, Dominique Trouet, Reiner Mauel, Amélie Dendooven, Anne Hoorens, Jo Van Dorpe, Marleen Praet, Caroline Geers, Evelyne Lerut, Priyanka Koshy, Tania Roskams, Selda Aydın, Vasiliki Siozopoulou, Anne‐Marie Schelfhout, Hendrik De Raeve, Edwin Steenkiste, Francesca Dedeurwaerdere, Ignace Dalle, Kristof Cokelaere, Stijn Deloose, Pascale De Paepe, Peter Van Eyken
Abstract
Background: The Flemish Collaborative Glomerulonephritis Group (FCGG) registry is the first population-based native kidney biopsy registry in Flanders, Belgium. In this first analysis, we report on patient demographics, frequency distribution and incidence rate of biopsied kidney disease in adults in Flanders. Methods: From January 2017 to December 2019, a total of 2054 adult first native kidney biopsies were included. A 'double diagnostic coding' strategy was used, in which every biopsy sample received a histopathological and final clinical diagnosis. Frequency distribution and incidence rate of both diagnoses were reported and compared with other European registries. Results: The median age at biopsy was 61.1 years (interquartile range, 46.1-71.7); male patients were more prevalent (62.1%) and biopsy incidence rate was 129.3 per million persons per year. Immunoglobulin A nephropathy was the most frequently diagnosed kidney disease (355 biopsies, 17.3% of total) with a similar frequency as in previously published European registries. The frequency of tubulointerstitial nephritis (220 biopsies, 10.7%) and diabetic kidney disease (154 biopsies, 7.5%) was remarkably higher, which may be attributed to changes in disease incidence as well as biopsy practices. Discordances between histopathological and final clinical diagnoses were noted and indicate areas for improvement in diagnostic coding systems. Conclusions: The FCGG registry, with its 'double diagnostic coding' strategy, provides useful population-based epidemiological data on a large Western European population and allows subgroup selection for future research.